Norepinephrine and epinephrine enter the bloodstream when sympathetic stimulation is provided to the:

Norepinephrine and epinephrine are secreted into the bloodstream when sympathetic stimulation is provided to the Adrenal Medulla. The sympathetic nervous system (SNS) originates in the spinal cord and it’s responsible for the activation of physiological changes that occur during the fight-or-flight response.